Thirty years ago, this magazine published “The End of Nature,” a long article about what we then called the greenhouse effect. I was in my twenties when I wrote it, and out on an intellectual limb: climate science was still young. But the data were persuasive, and freighted with sadness. We were spewing so much carbon into the atmosphere that nature was no longer a force beyond our influence—and humanity, with its capacity for industry and heedlessness, had come to affect every cubic metre of the planet’s air, every inch of its surface, every drop of its water. Scientists underlined this notion a decade later when they began referring to our era as the Anthropocene, the world made by man.

I was frightened by my reporting, but, at the time, it seemed likely that we’d try as a society to prevent the worst from happening. In 1988, George H. W. Bush, running for President, promised that he would fight “the greenhouse effect with the White House effect.” He did not, nor did his successors, nor did their peers in seats of power around the world, and so in the intervening decades what was a theoretical threat has become a fierce daily reality. As this essay goes to press, California is ablaze. A big fire near Los Angeles forced the evacuation of Malibu, and an even larger fire, in the Sierra Nevada foothills, has become the most destructive in California’s history. After a summer of unprecedented high temperatures and a fall “rainy season” with less than half the usual precipitation, the northern firestorm turned a city called Paradise into an inferno within an hour, razing more than ten thousand buildings and killing at least sixty-three people; more than six hundred others are missing. The authorities brought in cadaver dogs, a lab to match evacuees’ DNA with swabs taken from the dead, and anthropologists from California State University at Chico to advise on how to identify bodies from charred bone fragments…

Scientists have warned for decades that climate change would lead to extreme weather. Shortly before the I.P.C.C. report was published, Hurricane Michael, the strongest hurricane ever to hit the Florida Panhandle, inflicted thirty billion dollars’ worth of material damage and killed forty-five people. President Trump, who has argued that global warming is “a total, and very expensive, hoax,” visited Florida to survey the wreckage, but told reporters that the storm had not caused him to rethink his decision to withdraw the U.S. from the Paris climate accords. He expressed no interest in the I.P. C.C. report beyond asking “who drew it.” (The answer is ninety-one researchers from forty countries.) He later claimed that his “natural instinct” for science made him confident that the climate would soon “change back.” A month later, Trump blamed the fires in California on “gross mismanagement of forests.”

Human beings have always experienced wars and truces, crashes and recoveries, famines and terrorism. We’ve endured tyrants and outlasted perverse ideologies. Climate change is different. As a team of scientists recently pointed out in the journal Nature Climate Change, the physical shifts we’re inflicting on the planet will “extend longer than the entire history of human civilization thus far.”

The poorest and most vulnerable will pay the highest price. But already, even in the most affluent areas, many of us hesitate to walk across a grassy meadow because of the proliferation of ticks bearing Lyme disease which have come with the hot weather; we have found ourselves unable to swim off beaches, because jellyfish, which thrive as warming seas kill off other marine life, have taken over the water. The planet’s diameter will remain eight thousand miles, and its surface will still cover two hundred million square miles. But the earth, for humans, has begun to shrink, under our feet and in our minds.

“Climate change,” like “urban sprawl” or “gun violence,” has become such a familiar term that we tend to read past it. But exactly what we’ve been up to should fill us with awe. During the past two hundred years, we have burned immense quantities of coal and gas and oil—in car motors, basement furnaces, power plants, steel mills—and, as we have done so, carbon atoms have combined with oxygen atoms in the air to produce carbon dioxide. This, along with other gases like methane, has trapped heat that would otherwise have radiated back out to space.

There are at least four other episodes in the earth’s half-billion-year history of animal life when CO2 has poured into the atmosphere in greater volumes, but perhaps never at greater speeds. Even at the end of the Permian Age, when huge injections of CO2 from volcanoes burning through coal deposits culminated in “The Great Dying,” the CO2 content of the atmosphere grew at perhaps a tenth of the current pace. Two centuries ago, the concentration of CO2 in the atmosphere was two hundred and seventy-five parts per million; it has now topped four hundred parts per million and is rising more than two parts per million each year. The extra heat that we trap near the planet every day is equivalent to the heat from four hundred thousand bombs the size of the one that was dropped on Hiroshima.

As a result, in the past thirty years we’ve seen all twenty of the hottest years ever recorded. The melting of ice caps and glaciers and the rising levels of our oceans and seas, initially predicted for the end of the century, have occurred decades early. “I’ve never been at . . . a climate conference where people say ‘that happened slower than I thought it would,’ ” Christina Hulbe, a New Zealand climatologist, told a reporter for Grist last year. This past May, a team of scientists from the University of Illinois reported that there was a thirty-five-per-cent chance that, because of unexpectedly high economic growth rates, the U.N.’s “worst-case scenario” for global warming was too optimistic. “We are now truly in uncharted territory,” David Carlson, the former director of the World Meteorological Organization’s climate-research division, said in the spring of 2017, after data showed that the previous year had broken global heat records.